Folding mechanism



C. S. CRAFTS FOLDING MECHANISM Filed March 19. 1951 4 Sheets-Sheet l July 17, 1934. c. s. CRAFTS FOLDING MECHANISM Filed March 19. 1931 4 Sh tsheet 2 I, I w ilihlil" 1 M 1 Lil A" wil I Hz m 5 3 "lfl 3/ 21 1 :4 m1 2%;

30 III I July 17, 1934. c. s. CRAFTS 1,966,885

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Patented July 17, 1934 UNITED STATES FOLDING MECHANISM Curtis S. Crafts, Oak Park, Ill., assignor to Goss Printing Press Company, Chicago, 111., a corporation of Illinois Application March 19, 1931, Serial No. 523,796

18 Claims.

The present invention relates to folding mechanisms and more particularly to rotary folding mechanisms for folding groups of printed sheets at a relatively high speed.

5 Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities 10 and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

Of the drawings:

Fig. 1 is a central vertical section through the preferred and illustrative embodiment of the invention, with many of the parts omitted;

Fig. 2 is a fragmentary detailed section of the cooperating folding blade and jaw in accordance with the present invention;

Fig. 3 is a similar view showing a common form of folding mechanism as heretofore generally constructed;

Fig. 4 is a diagrammatic View illustrating several positions of the folding blade and jaw shown in Figure 3;

Fig. 5 is a similar view showing the corresponding positions of the folding blade and jaw of Fig. 2 and in accordance with the present invention.

The present invention has for its object the provision of a folding mechanism for use in connection with printing presses and more particularly a folding mechanism in which the line of fold is always maintained in the same position on the folding cylinders. A further object of the invention is the provision of a folding mechanism for folding a group of sheets in which is eliminated the tendency of-the inner sheets to be combed off as the folding blade is withdrawn fromthe folding jaw.

Heretofore, in the conventional form of folding mechanism, a pair of folding cylinders have been employed, one of these cylinders carrying folding jaws, and the other cylinder carrying folding blades for folding a group of sheets into the folding jaws. In this mechanism as heretofore constructed, the point of the folding blade runs very slightly faster than the outer edge of the cooperating folding jaw and tends to lift the movable jaw members, thereby reducing the heavy pressure exerted by this jaw necessary to maintain the sheets tightly gripped. Also, the blade has been positioned so that it is not withdrawn parallel to the jaw faces of the folding jaw and in withdrawing the blade there was a twisting of the blade tending to pry open the jaw and release the sheets, at the same time wearing the point of the folding blade and the outer edge of the jaw.

In accordance with the preferred form of the present invention, the folding blades mounted on the blade cylinder are held in a non-radial position during folding and cooperate with the folding jaws of an adjacent jaw cylinder, the blade folding the group of sheets into the folding jaw where they are held until delivery. The point of the folding blade travels at the same speed as the outer edge of the folding jaw and maintains a constant spacing from the fixed folding jaw while folding. This constant spacing prevents lifting of the movable jaw by faster travel of the blade while the non-radial setting of the blade prevents prying open of the jaws, reduces wear on the blade and jaw, and also causes the blade to be withdrawn while parallel to the fixed jaw face. The cylinders are preferably geared together, and the blade and jaw are given the same speed by making the diameter of the jaw cylinder slightly larger than the pitch diameter of the gear therefor, while the pitch diameter of the blade cylinder gear is slightly smaller than the circle described by the point or outer edge of the blade and larger than the diameter of the blade cylinder.

It will be understood that the foregoing general description and the following detailed description as well are exemplary and explanatory of the invention but are not restricted thereon.

The folding mechanism of the present invention comprises generally a cylinder 10 carrying one or more folding blades 11 and a cooperating cylinder 12 carrying one or more folding jaws 31, the cylinders being mounted closely adjacent to each other and geared together, so that the folding blades register with the folding jaws as the cylinders rotate.

As is usual in this general type of mechanism, the printed sheets to be folded are presented to the blade cylinder, the heads of the sheets are securely held on the blade cylinder and on rotation of the cylinders, the folding blade forces the sheets along their mid-portion into a registering folding jaw which takes the sheets by the fold. On further rotation, the blade is withdrawn leaving the group of folded sheets held by the jaw which is later opened to release the folded product and deliver it.

In the present illustrative embodiment, the blade cylinder 10 is approximately three-fourths the diameter of the jaw cylinder 12 and is provided with three folding blades 11 which cooperate with a pair of diametrically opposed folding jaws 31 carried by the jaw cylinder. In addition, the blade cylinder 10 is provided with the usual sheet-holding devices, such as grippers or impaling pins, and such other devices as may be desired. As these form no part of the present invention and may be of i any desired form, they are not shown in the drawings.

As embodied, the blade cylinder 10 is provided with three longitudinally extending blade-receiving slots 14 formed in the surface of the cylinder in which the folding blades 11 are mounted, these slots having parallel side walls 15, a fiat bottom 16 and extending from one end of the cylinder to the other.

'The folding blades employed in the present embodiment, and secured within the slots comprise a relatively thin steel member, bevelled on its outer end, as at 18, and provided with a rib or strip 19 securely fastened to its inner end. The blades are each mounted in a block 20 which is provided with a slot to receive the blade and rib 19 and the blade is secured therein by means of the retaining strip21 extending from one end of the block to the other and held thereon by'meansof screws 22. The strip 21 overlies a portion of the slot and engages the rib 19 to prevent outward movement of the blade. The slot is'preferably made larger than the thickness of the'bl'ade and when assembled, the blade is resiliently held against the retaining strip 21 by means of springs 23 spaced along the length of the blade and seated in the block. The blocks are also provided with adjusting screws 24, which may be screwed inorout to accurately position the blades 'circumferentially of the cylinder. Screws25 are also provided passing through slots 26in blockf20 and threaded into the bottom of the slots-14 to securely hold the blade in' any of its adjusted positions. v

According to the present invention, the folding blades are not held in a' radial position; on the cylinder, but are at a slight angle toa radius passing through the blade, as clearly shown in Figure 5 of the drawings."

Thejaw cylinder'of the present embodiment is provided with two folding jaws, of conventional construction into which the sheets are folded by the action'of the folding blades. These jaws comprise a stationary jaw 30'at the periphery of the jaw cylinder 12 and a movable jaw 31 mounted on a shaft 32, which is rocked back and forth in the usual manner'to open and close the jaws as the cylinder rotates.

Means are also provided for driving the folding blade at the same peripheral speed as the outer edge of the folding jaw and as embodied, these cylinders are geared together by gears mounted on the cylinder shafts. The jaw cylinder carries a gear 35 mounted on its shaft while the blade cylinder carries a'cooperating gear 36 mounted onits shaft. The pitch'diameter of the driving 'gear 35' for the jaw cylinder is slightly smaller than'the diameter of the jaw cylinder, while the pitch diameter of the driving gear 36 for the bladecylin'der is'very slightly smaller than the circle described by the outer point of the folding blade--11, thereby making the linear speed of the point of the folding blade the same as the speed of the outer edge of the folding aws.

To facilitate an understanding of the present invention, a form of folding mechanism hitherto generally employed is illustrated in Figures 3 and 4 of the drawings. As shown in these figures, the folding blade cylinder 40 was provided with resiliently mounted folding blades 41 set substantially radially of the cylinder and held in radial position by means of the springs 42. The jaw cylinder. 43 was substantially the same as that shown in the illustrative embodiment of the present invention and was provided with jaws, each comprising a stationary jaw 44 and a movable jaw 45 the movable jaw being rocked back and forth byoscillation of the jaw shaft 46 to grip and fold the sheets S.

.Means were also provided for driving the folding blade cylinder and jaw cylinder together, and for this purpose gear 47 was fixed to the jaw cylinder shaft and meshed with a gear 48 fixed to the blade cylinder shaft. The pitch diameter of the gear 47, represented by the circle A, was slightly larger than the diameter of the jaw cylinder 43, and the diameter of the blade cylinder 40 was smaller than the pitch diameter (circle B) of the gear 48 therefor, as well as smaller than the circle described by the folding blade 41. Due to this gear ratio the point of the folding blade 41 travelled slightly faster than the outer edge of the folding cylinder jaw 44, tending to lift the movable jaw member 45 away fromthestationary jaw 44, against the tension of the jaw-closing spring.

Figure 4 illustrates diagrammatically several successive positions 4a, 4b, 4c, 4d and 4e of the folding blade and folding jaw, as heretofore commonly constructed. As shown the jaws 44, 45 and folding blade 41 are moving upwardly. In the lowermost position 4a, the folding blade 41 is entering the open folding jaw and is very-close to the fixed or stationary jaw 44, being separated therefrom only by the thickness of thegroup of sheets to be folded (not shown). On further rotation of the cylinders, the blade continues to enter between the jaws (4b), folding the group of sheets, and in the central position 40, the movable jaw 45 is closed to tightly hold the folded group of sheetsby the fold; As will be seen from the showing of the next position 4d, the folding jaw remains closed against the sheets as blade 41 is gradually pulled out of the jaws, but due to the faster travel of the blade, is farther from the fixed jaw at 4e than at position 4a. When operating at slow speeds, the pressure with which the upper or movable jaw 45 was pressed against the fixed jaw 44 often was sufficient to compress the blade supporting springs 42 and keep the folded group of sheets S tightly held in the jaw. However, in actual operation, the movable jaw 45 was lifted from the stationary jaw 44, reducing the pressure with which the sheets were gripped along their line of fold. Due to this reduced gripping orholding pressure, the inner sheets often slipped around the point of'the folding blade.

As is also shown by these figures, after the folding blade has passed its central position, the

folding blade 41 tends to be fulcrumed at the outer edge of the folding jaw 44, as at 4d, and the point of the blade tends to pry up on the movable jaw 45. This action tended to wear the outer edge or point of the stationary jaw.

Figure 5'of the drawings shows the operation of the present preferred and illustrative embodiment of the invention in a diagrammatic manher, and also shows the differences in operation as compared with the mechanism shown in Figures 3 and 4. According to the present invention, the folding blade 11 is held non-radially of the cylinder 10. .As will be seen from these successive stages, the point of the blade 11, during the entire folding operation or from the time the point enters the jaws 30, 31 until it is retracted therefrom, it is maintained at a constant spacing from the fixed or stationary jaw 38. This spacing is equal to the thickness of the group of sheets, not shown, and can be accordingly varied by moving the screws 24. As the point of the blade 11 travels at the same speed as the outer edge of the folding jaw 30, the spacing is maintained always constant and there is no lifting of the movable jaw 31 by the blade. The blade-supporting springs 23, according to the present invention, serve merely to take up uneven or irregular motion of the blade 11, such as is due to wear or inaccurate adjustment of the several parts.

As will also be seen from Figure 5 of the drawings, there is no tendency of the blade to pry up the movable jaw 31 from the fixed jaw, as there is no faster travel of the blade or pivoting of the blade about the outer edge of the jaw. The blade enters the folding jaw and the angle between the blade and the face 'of the lower jaw continually decreases during the inward movement of the blade (5a, 5b) and also during the Withdrawal of the blade (5d, 56) and as the blade is fully withdrawn (5e) the blade and fixed jaw face are parallel to each other. Thus, wear of the jaw faces and blade is avoided and there is no tendency of the blade to relieve the pressure exerted by the movable jaw as it holds the group of folded sheets by the fold.

After passing position 5e, the folding blade finally becomes parallel to a line connecting the centers of cylinders 10 and 12.

The cylinders 10 and 12 are, in the illustrative embodiment, spaced from each other a distance slightly greater than the thickness of the group of sheets to be folded, and the center of this spacing lies inside the pitch circle of gear 36.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What I claim is:--

l. The method of folding a group of sheets which includes holding the sheets adjacent to an open folding jaw, pressing a folding blade against the sheets to force them into the jaw, simultaneously closing the jaw and moving the sheets, the outer edge of the jaw and the point of the blade at the same peripheral speed while withdrawing the blade.

2. The method of folding a group of sheets which includes holding the sheets adjacent to an open folding jaw having a fixed and a movable jaw member, continuously moving the outer edge of the jaw and the point of a cooperating folding blade at the same peripheral speed, pressing the lade into the open jaw to fold the sheets, closing the jaw and withdrawing the blade while it is parallel to the jaw faces.

3. A folding mechanism including in combination a jaw cylinder having fixed and movable jaw faces, a blade cylinder having folding blades mounted thereon to be projected into said jaws and means for driving the point of said folding blade at substantially the same peripheral speed as the outer edge of the fixed jaw face while the blade is projected between the jaw faces of one of the jaws.

4. A folding mechanism including in combination a jaw cylinder having. fixed and movable jaw faces, a bladecylinder having folding blades mounted thereon to be projected into said jaws and withdrawn therefrom and gearing. for driving said jaw cylinder and blade cylinder together, the parts being so proportioned that the point of the blade moves at the same peripheral speed as the outer edge of the fixed jaw. 5. A folding mechanism including incombina" tion a jaw cylinder having fixed and movable jaw faces, a blade cylinder having folding blades mounted thereon to fold a plurality of sheets between said jaw faces and means for driving the point of the blade at the same peripheral speed as the outer edge of the jaw faces.

6. A folding mechanism including in combination a jaw cylinder having fixed and movable jaw faces, a blade cylinder having folding blades mounted thereon to be projected into said jaws, means for projecting and withdrawing the blade between the jaw faces, the outer edge of. said blade being driven at substantially the same peripheral speed as the outer edge of said jaw and so positioned as to prevent the bearing of the blade against the face of the fixed jaw.

7. A folding mechanism including in combination a jaw cylinder having fixed and movable jaws, said fixed jaws having radial faces, a cooperating blade cylinder carrying a folding blade to be projected into one of said jaws during rotation of the cylinder, said blade being positioned non-radially and inclined rearwardly to the direction of rotation of said blade cylinder and means for withdrawing the blade from the jaw while the blade is parallel to the fixed jaw face.

8. A folding mechanism including in combination a jaw cylinder having fixed and movable jaw faces, a resiliently mounted blade cylinder having folding blades mounted thereon to fold a plurality of sheets between said jaw faces and means for driving the point of the blade at the same peripheral speed as the outer edge of the jaw faces.

9. A folding mechanism including in combination a jaw cylinder having fixed and movable jaw faces, a blade cylinder having resiliently mounted, non radial folding blades mounted thereon and inclined rearwardly to the direction of rotation of said blade cylinder to fold a plurality of sheets between said jaw faces, means for minutely and variably positioning the blade circumferentially of the cylinder, said blade being parallel to the jaw face at the time of its withdrawal from the jaw to prevent twisting of the blade while it is between the jaw faces.

10. A folding mechanism for printing presses including in combination a jaw cylinder and a cooperating blade cylinder, the blade carried by said blade cylinder being held non-radially to its supporting cylinder while folding.

11. A folding mechanism for printing presses including in combination a jaw cylinder having fixed and movable jaws, said fixed jaw having a radial face, a cooperating blade cylinder carrying a folding blade, said blade being of such a length and set at such an angle that the blade is withdrawn from the jaw while the blade is parallel to the fixed jaw face.

12. A folding mechanism for printing presses including in combination a jaw cylinder having fixed and movable jaws, said fixed jaw having a radial face, a cooperating blade cylinder carrying a folding blade to be projected into one of said jaws by rotation of the cylinders, said blade being positioned non-radially to its supporting cylinder whereby the point of the blade is withdrawn from the jaw while the blade is parallel to the fixed jaw face.

13. A folding mechanism for printing presses including in combination a jaw cylinder of slightly larger diameter than the pitch diameter of the driving gear therefor and a blade cylinder of smaller diameter than the pitch diameter of its driving gear whereby the surface of the blade cylinder is driven slightly slower than the surface of the jaw cylinder.

14. A folding mechanism for printing presses including in combination a jaw cylinder and a cooperating blade cylinder geared together, the gear ratio between the two cylinders being such as to drive the jaw cylinder slightly faster than the peripheral speed of the blade cylinder.

I 15. A folding mechanism for printing presses including in combination a jaw cylinder and a cooperating blade cylinder having their diameters in a predetermined ratio and driving gears therefor in approximately the same ratio, the gear for the jaw cylinder being slightly smaller than that called for by the predetermined ratio.

16. A folding mechanism for printing presses including in combination a jaw cylinder and a cooperating blade cylinder spaced from each other approximately the thickness of the group of sheets to be folded and driving gears therefor, the center line of the group of sheets lying inside the pitch circle of the gear for the blade cylinder.

17. A folding mechanism including in combination a jaw cylinder having fixed and movable jaw faces, a blade cylinder having folding blades mounted thereon to be projected into said jaws and means for moving the folding blade with its point at the same peripheral speed as the outer edge of the jaw, the blade being angularly positioned with respect to its cylinder to press the blade point always against the fixed jaw face while it is Within the jaw.

18. A folding mechanism including in combination a jaw cylinder having folding blades mounted thereon, said blades being positioned non-radially of the cylinder and rearwardly inclined with reference to the direction of rotation of said cylinder, a jaw cylinder having fixed and movable jaw faces to cooperate with said folding blade, and means for driving the point of the blade and the outer edge of said jaws at the same peripheral speed for preventing movement of the movable jaw by the blade and twisting of the blade during the folding operation.

CURTIS S. CRAFTS. 

